1. Field of the Invention
The present invention relates to a method and system for dispensing a material solution on a substrate, and, more particularly, to a method and system for dispensing a material solution on a substrate in order to reduce the volume of dispensed fluid.
2. Description of the Related Art
In material processing methodologies, pattern etching includes the application of a thin layer of light-sensitive material, such as photoresist, to an upper surface of a substrate that is subsequently patterned in order to provide a mask for transferring this pattern to the substrate during etching. The patterning of the light-sensitive material generally involves coating an upper surface of the substrate with a thin film of light-sensitive material, exposing the thin film of light-sensitive material to a radiation source through a reticle (and associated optics) using, for example, a micro-lithography system, followed by a developing process during which the removal of the irradiated regions of the light-sensitive material occurs (as in the case of positive photoresist), or the removal of non-irradiated regions occurs (as in the case of negative resist) using a developing solvent.
During the coating process, a substrate is positioned on a substrate holder, and it is rotated at high speed, i.e., several thousand or tens of thousand revolutions per minute (rpm), while resist solution is dispensed on an upper surface of the substrate. When, for example, the resist solution is dispensed at the center of the substrate, the resist solution spreads radially across the substrate due to centrifugal forces imposed by the substrate rotation. In order to reduce the costs associated with resist solution dispensing, the total volume (or shot size) of resist solution that is dispensed is minimized, which places greater emphasis on the design of dispensing parameters (i.e., rotation rate, dispensing rate, resist solution fluid properties, etc.) sufficient to achieve a uniform coating on the substrate.